The present invention relates to a diaphragm clutch mechanism, particularly for a motor vehicle, of the kind comprising a first generally annular part known as the cover adapted to be peripherally attached to a first plate known as the reaction plate or flywheel, and also to be rotationally fixed to a second plate known as the pressure plate; a second generally annular part known as the diaphragm and comprising a peripheral portion forming a Belleville spring for acting on the pressure plate and a central portion divided into radial fingers for acting on a clutch release bearing; and connection means fastening the diaphragm to the cover and comprising flat, thin lugs extending from the cover and having an axial portion and a radial portion, which portions define between them a wedging bend, and an annular supporting ring wedged in the bend, the cover and the ring defining directly or indirectly, for the diaphragm, a primary fulcrum support and a secondary fulcrum support, these supports being disposed substantially opposite one another.
As a rule in clutch mechanisms of this type the supporting ring is elastic and axially applies the diaphragm against the primary support of the cover with a predetermined elastic clamping load which may be of any suitable value higher or lower than or substantially equal to the clutch release force, this being the force that is applied by means of the clutch release bearing to the diaphragm in order to disengage the clutch.
Clutch mechanisms of this type may perform satisfactorily. Nevertheless, they have the disadvantage that, however low the abovementioned elastic clamping load is, considerable friction is introduced at the primary and secondary supports between which the diaphragm is gripped.
A main object of the present invention is to provide a diaphragm clutch mechanism, particularly for a motor vehicle, which possesses all the advantages inherent in mechanisms of the kind described above, but which is free from this disadvantage.